re PR target/64876 (Regressions in gcc-testresults for powerpc64 gccgo in 5.0…

re PR target/64876 (Regressions in gcc-testresults for powerpc64 gccgo in 5.0 due to change for static chain for closures (219776))

	PR target/64876
	* config/rs6000/rs6000.c (chain_already_loaded): New function.
	(rs6000_call_aix): Use it.

From-SVN: r220463

gcc/ChangeLog

+2015-02-06  Alan Modra  <amodra@gmail.com>
+
+	PR target/64876
+	* config/rs6000/rs6000.c (chain_already_loaded): New function.
+	(rs6000_call_aix): Use it.
+
 2015-02-05  Jan Hubicka <hubicka@ucw.cz>
 
 	* ipa-cp.c (ipa_value_from_jfunc, ipa_context_from_jfunc): Add bounds

gcc/config/rs6000/rs6000.c

@@ -32919,6 +32919,28 @@ rs6000_legitimate_constant_p (machine_mode mode, rtx x)
 }
 
 
+/* Return TRUE iff the sequence ending in LAST sets the static chain.  */
+
+static bool
+chain_already_loaded (rtx_insn *last)
+{
+  for (; last != NULL; last = PREV_INSN (last))
+    {
+      if (NONJUMP_INSN_P (last))
+	{
+	  rtx patt = PATTERN (last);
+
+	  if (GET_CODE (patt) == SET)
+	    {
+	      rtx lhs = XEXP (patt, 0);
+
+	      if (REG_P (lhs) && REGNO (lhs) == STATIC_CHAIN_REGNUM)
+		return true;
+	    }
+	}
+    }
+  return false;
+}
 
 /* Expand code to perform a call under the AIX or ELFv2 ABI.  */
 
@@ -33002,7 +33024,9 @@ rs6000_call_aix (rtx value, rtx func_desc, rtx flag, rtx cookie)
 	     originally direct, the 3rd word has not been written since no
 	     trampoline has been built, so we ought not to load it, lest we
 	     override a static chain value.  */
-	  if (!direct_call_p && TARGET_POINTERS_TO_NESTED_FUNCTIONS)
+	  if (!direct_call_p
+	      && TARGET_POINTERS_TO_NESTED_FUNCTIONS
+	      && !chain_already_loaded (crtl->emit.sequence_stack->last))
 	    {
 	      rtx sc_reg = gen_rtx_REG (Pmode, STATIC_CHAIN_REGNUM);
 	      rtx func_sc_offset = GEN_INT (2 * GET_MODE_SIZE (Pmode));